The role of immunoglobulins in T cells and the organization of immunoglobulin genes in immune and non-immune cells will be investigated. Specifically, we will analyze the chromatin conformation of immunoglobulin genes in T lymphocytes from various sources. The complete structure of mouse lambda genes will be determined by restriction mapping, electron microscopy and partial DNA sequencing of lambda genes from a genomic library. The organization and function of highly repetitive and inversely repeated DNA flanking immunoglobulin genes will be studied in genomic and cloned DNAs. Lastly, somatic mutations affecting antibody diversity will be further studied.